New study compares injury caused by explosion vs. mechanical force

Most concussions are the result of mechanical forces that occur when your head is hit in a car crash or when playing sports. But 50 to 80 percent of military personnel who suffer a concussion are hurt by intense pressure waves that result from a blast of an improvised explosive device.

A new study finds differences in brain activity and behavior depending on whether a concussion is caused by an explosion versus a mechanical force.

"There have been a number of animal studies to demonstrate differences between blast versus mechanical injuries. Our study is the first to demonstrate this in humans," explained Dr. Stephen Rao, a Cleveland Clinic Neuroscientist who helped lead the study.

Rao and his team of researchers studied differences between blast and mechanical causes of concussion among nearly 100 military personnel and civilians. They asked their subjects to perform a task measuring their ability to inhibit a response while recording their brain activity with an MRI scanner. They found that blast-related concussions caused a different pattern of brain activity than mechanical concussions.

"The causes of the injury can make a very important difference in the way that's expressed behaviorally and also in the way the brain is altered by the traumatic brain injury," said Rao.

Rao says suffering a blast related concussion, and not having the ability to control impulses as a result, may lead to behaviors like gambling or heavy drinking. He says, oftentimes, behaviors like this may be confused with the side-effect of posttraumatic-stress disorder, when it's actually caused by the brain injury.

Rao adds more studies are needed, but the results could help doctors use this imaging technology to put together a more specialized treatment plan tailored to how the person was injured.

"Because we are showing differences in the way the brain is affected by blast versus mechanical injuries it is conceivable that the types of rehabilitation efforts and the types of rehabilitation strategies may be very different for the two types of brain injuries," he said.